EVOLUTION OF THE LEFT-VENTRICULAR FILLING PATTERN IN THE FIRST YEAR AFTER AN ACUTE MYOCARDIAL-INFARCTION - THE INFLUENCE OF INFARCT SIZE

Objectives. Acute myocardial infarction induces diastolic dysfunction as a result of the alteration of left ventricular relaxation and stiff ness caused by ischemia and fibrosis. This study analyzes the associat ion of infarct size with the diastolic filling pattern and the evoluti on of the latter during the first postinfarction year. Patients and me thods. The study group consisted of 68 patients with a first acute myo cardial infarction treated with thrombolytic agents. A Doppler echocar diography was performed at 8 +/- 2, 32 +/- 7 and 370 +/- 23 days after infarction. Five measurements of the ratio between E and A waves peak velocities (E/A ratio) and of the E deceleration time (EDT, ms) were averaged in each echocardiographic study. The patients were divided ac cording to infarct size into a large infarct group (creatine kinase > 1,000 U/ml; 1,913 +/- 883; n = 26) and a smallinfarct group (creatine kinase < 1,000 U/ml; 556 +/- 227; n = 42). Results. The large infarct group exhibited a greater E/A ratio and shorter EDT than the small inf arct group in the first week (E/A ratio: 1.4 +/- 0.7 vs 0.8 +/- 0.3; p = 0.0001; EDT: 159 +/- 49 vs 192 +/- 56; p 0.02) and at one month (E/ A ratio: 1.2 +/- 0.7 vs 0.9 +/- 0.3; p = 0;01; EDT: 170 +/- 55 vs 207 +/- 40; p = 0.004); however no differences were observed between eithe r group at one year in either E/A ratio (0.8 1 0.2 vs 0.9 +/- 0.4; NS) or EDT (207 +/- 44 vs 219 +/- 54; NS). In the large infarct group, E/ A ratio decreased and EDT increased at one year compared to the first week (E/A ratio: p = 0.0004; EDT: p = 0.0001) and the first month (E/A : p = 0.02; EDT: p = 0.003); in contrast, in the small infarct group t here were no significant differences in EIA ratio nor EDT during the f irst year postinfarction. Conclusions. In the first month postinfarcti on, large infarcts exhibit a greater E/A ratio and shorter EDT than sm all infarcts. The evolution of large infarcts is characterized by an a ttenuation of this pattern, with a progressive reduction of E/A ratio and prolongation of EDT during the first year postinfarction.